Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Solar system ’fossils’ discovered by Hubble Telescope

08.09.2003


Astronomers using NASA’s Hubble Space Telescope have discovered three of the faintest and smallest objects ever detected beyond Neptune. Each lump of ice and rock is roughly the size of Philadelphia and orbits just beyond Neptune and Pluto, where they may have rested since the formation of the solar system 4.5 billion years ago. The objects reside in a ring-shaped region called the Kuiper Belt, which houses a swarm of icy rocks that are leftover building blocks, or "planetesimals," from the solar system’s creation.



The results of the search were announced by a group led by Gary Bernstein of the University of Pennsylvania at today’s meeting of NASA’s Division of Planetary Sciences in Monterey, Calif.

The study’s big surprise is that so few Kuiper Belt members were discovered. With Hubble’s exquisite resolution, Bernstein and his co-workers expected to find at least 60 Kuiper Belt members as small as 10 miles in diameter -- but only three were discovered.


"Discovering many fewer Kuiper Belt Objects than was predicted makes it difficult to understand how so many comets appear near Earth since many comets were thought to originate in the Kuiper Belt," said Bernstein, associate professor of physics and astronomy at Penn. "This is a sign that perhaps the smaller planetesimals have been shattered into dust by colliding with each other over the past few billion years."

Bernstein and his colleagues used Hubble to look for planetesimals that are much smaller and fainter than can be seen from ground-based telescopes. Hubble’s Advanced Camera for Surveys was pointed at a region in the constellation Virgo over a 15-day period in January and February. A bank of 10 computers on the ground worked for six months searching for faint moving spots in the Hubble images.

The three small objects the astronomers spotted - given the prosaic names 2003 BF91, 2003 BG91 and 2003 BH91 - range in size from 15 to 28 miles and are the smallest objects ever found beyond Neptune. At their current locations, these objects are a billion times fainter than the dimmest objects visible to the naked eye. But an icy body of this size that escapes the Kuiper Belt to wander near the sun can become visible from Earth as a comet as the wandering body starts to evaporate and form a surrounding cloud.

Astronomers are probing the Kuiper Belt because the region offers a window on the early history of our solar system. The planets formed more than 4 billion years ago from a cloud of gas and dust that surrounded the infant sun. Microscopic bits of ice and dust stuck together to form lumps that grew from pebbles to boulders to city- or continent-sized planetesimals. The known planets and moons are the result of collisions between planetesimals. In most of the solar system, all of the planetesimals have either been absorbed into planets or ejected into interstellar space, destroying the traces of the early days of the solar system.

Around 1950, Gerard Kuiper and Kenneth Edgeworth proposed that in the region beyond Neptune there are no planets capable of ejecting the leftover planetesimals, so there should be a zone, now called the Kuiper Belt, filled with small, icy bodies. Despite many years of searching, the first was not discovered until 1992; nearly 1,000 have since been discovered from telescopes on the ground. Most astronomers now believe that Pluto, discovered in 1930, is in fact a member of the Kuiper Belt.

Astronomers now use the Kuiper Belt to learn about the history of the solar system, much as paleontologists use fossils to study early life. Each event that affected the outer solar system -- such as possible gravitational disturbances from passing stars or long-vanished planets -- is frozen into the properties of the Kuiper Belt members that we see today.

If the Hubble telescope could search the entire sky, it would find perhaps a half-million planetesimals, but, if collected into a single planet, they would be only a few times larger than Pluto. The new Hubble observations, combined with the latest ground-based Kuiper Belt surveys, reinforce the idea that Pluto itself and its moon Charon are just large Kuiper Belt members. Why the Kuiper Belt planetesimals did not form a larger planet and why there are fewer small planetesimals than expected are questions that will be answered with further study of the Kuiper Belt. This will help to understand how planets might have formed around other stars as well.

The new results from Hubble were reported by Bernstein and David Trilling of Penn; Renu Malhotra of the University of Arizona; Lynne Allen of the University of British Columbia; Michael Brown of the California Institute of Technology; and Matthew Holman of the Harvard-Smithsonian Center for Astrophysics. The results have been submitted to the Astronomical Journal for publication.

Steve Bradt | EurekAlert!
Further information:
http://www.upenn.edu/

More articles from Physics and Astronomy:

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>